If `cos e cA+secA=cos e c B+s e cB ,` prove that: `"tanAtanB"=cot(A+B)/2`

If "cosec"A + secA="cosec"A+secB , prove that: tanA.tanB=cot(A+B)/(2)

If cosecA+secA=cosecB+secB Prove that tanAtanB=cot((A+B)/2) .

Prove that: cot^2A-tan^2A=4\ cot2A cos e c2A

If A+B+C= pi and cos A=cos B. cosC,prove that cot B cot C= 1/2

Prove the following identity: (s e c A\ s e c B+t a n AtanB)^2-(s e c A\ t a n B+t a n A s e c B)^2=1

If a_1, a_2, a_n are in A.P. with common difference d!=0 , then the sum of the series sind[seca_1seca_2+seca_2seca_3+....+s e ca_(n-1)seca_n] is : a. cos e ca_n-cos e ca b. cota_n-cota c. s e ca_n-s e ca d. t a na_n-t a na

If a_1, a_2, a_n are in A.P. with common difference d!=0 , then the sum of the series sind[seca_1seca_2+(sec)_2seca_3+....+s e ca_(n-1)(sec)_n] is : a. cos e ca_n-cos e ca b. cota_n-cota c. s e ca_n-s e ca d. t a na_n-t a na

If three angles A,B, and C are in A.P.prove that: cot B=(s in A-s in C)/(cos C-cos A)

Prove: 1/(secA-1)+1/(secA+1)=2\ cos e c\ AcotA